. A drop (0.05 mL) of 12.0 M HCl is spread over a sheet of

Balance the following equations by inspection. (a) (b) (c) (d)

Balance the following equations by inspection. (a) (b) (c) (d)

Balance the following equations by inspection. (a) (b) (c) (d)

Balance the following equations by inspection. (a) (b) (c) (d)

Write balanced equations based on the information given. (a) solid magnesium oxide solid magnesium + oxygen gas CO2 + SO2 + H2O C6H5CH2SSCH2C6H5 + O2 Fe3O4 + HCl + Cl2 FeCl3 + H2O + O2 FeSO4 (b) (c) (d)

Write balanced equations based on the information given. (a) (b) (c) (d)

Write balanced equations to represent the complete combustion of each of the following in excess oxygen: (a) butane, (b) isopropyl alcohol, (c) lactic acid,

Write balanced equations to represent the complete combustion of each of the following in excess oxygen: (a) propylene, (b) thiobenzoic acid, (c) glycerol, CH2(OH)CH(OH)CH2OH. C3H6 ; C6H5COSH CH3CH(OH)CH3 ; CH3CH(OH)COOH. C4H10 ;

Write balanced equations to represent: (a) the decomposition, by heating, of solid ammonium nitrate to produce dinitrogen monoxide gas (laughing gas) and water vapor (b) the reaction of aqueous sodium carbonate with hydrochloric acid to produce water, carbon dioxide gas, and aqueous sodium chloride (c) the reaction of methane ammonia, and oxygen gases to form gaseous hydrogen cyanide (HCN) and water vapor

Write balanced equations to represent: (a) the reaction of sulfur dioxide gas with oxygen gas to produce sulfur trioxide gas (one of the reactions involved in the industrial preparation of sulfuric acid) (b) the dissolving of limestone (calcium carbonate) in water containing dissolved carbon dioxide to producecalcium hydrogen carbonate (a reaction producing temporary hardness in groundwater) (c) the reaction of ammonia and nitrogen monoxide to form nitrogen gas and water vapor

Write a balanced chemical equation for the reaction depicted below.

Write a balanced chemical equation for the reaction depicted below.

In an experiment, 0.689 g Cr(s) reacts completely with 0.636 g (g) to form a single solid compound. Write a balanced chemical equation for the reaction.

A 3.104 g sample of an oxide of manganese contains 1.142 grams of oxygen. Write a balanced chemical equation for the reaction that produces the compound from Mn(s) and O2(g).

Iron metal reacts with chlorine gas. How many grams of are obtained when 515 g reacts with excess Fe?

If 46.3 g is produced by the reaction how many grams each of and are consumed?

A laboratory method of preparing involves the decomposition of (a) How many moles of can be produced by the decomposition of 32.8 g (b) How many grams of must decompose to produce 50.0 g (c) How many grams of KCl are formed, together with 28.3 g in the decomposition of

A commercial method of manufacturing hydrogen involves the reaction of iron and steam. (a) How many grams of can be produced from 42.7 g Fe and an excess of (steam)? (b) How many grams of are consumed in the conversion of 63.5 g Fe to (c) If 14.8 g is produced, how many grams of must also be produced?

How many grams of are decomposed to yield 75.1 g Ag in this reaction? Ag(s) + CO2(g) + O2(g) (not balanced) Ag2CO3(s) " Ag2CO3 Fe3O4 H2 Fe3O4? H2O H2O(g) H2 3 Fe(s) + 4 H2O(g) " Fe3O4(s) + 4 H2(g) O2 , KClO3 ? O2 ? KClO3 KClO3? O2(g) 2 KClO3(s) " 2 KCl(s) + 3 O2(g) KClO3(s). O2(g) Cl2 P4 6 Cl2(g) + P4(s) 4 PCl3(l) PCl3 2 Fe(s) + 3 Cl2(g) 2 FeCl3(s) FeCl3 Cl2 O2

How many kilograms of are consumed to produce 125 kg in this reaction?

The reaction of calcium hydride with water can be used to prepare small quantities of hydrogen gas, as is done to fill weather-observation balloons. (a) How many grams of result from the reaction of 127 g with an excess of water? (b) How many grams of water are consumed in the reaction of 56.2 g (c) What mass of must react with an excess of water to produce molecules of

The reaction of potassium superoxide, is used in life-support systems to replace in expired air with The unbalanced chemical equation for the reaction is given below. (a) How many moles of are produced by the reaction of 156 g with excess (b) How many grams of are consumed per 100.0 g removed from expired air? (c) How many molecules are produced per milligram of consumed?

Iron ore is impure When is heated with an excess of carbon (coke), metallic iron and carbon monoxide gas are produced. From a sample of ore weighing 938 kg, 523 kg of pure iron is obtained. What is the mass percent by mass, in the ore sample, assuming that none of the impurities contain Fe?

Solid silver oxide, decomposes at temperatures in excess of 300 C, yielding metallic silver and oxygen gas. A 3.13 g sample of impure silver oxide yields 0.187 g What is the mass percent in the sample? Assume that is the only source of [Hint: Write a balanced equation for the reaction.] O2(g).

Decaborane, B10H14, was used as a fuel for rockets in the 1950s. It reacts violently with oxygen, O2, to produce B2O3 and water. Calculate the percentage by mass of B10H14 in a fuel mixture designed to ensure that B10H14 and O2 run out at exactly the same time. (Such a mixture minimizes the mass of fuel that a rocket must carry.)

The rocket boosters of the space shuttle Discovery, launched on July 26, 2005, used a fuel mixture containing primarily solid ammonium perchlorate, NH4ClO4(s), and aluminum metal. The unbalanced chemical equation for the reaction is given below. Al(s) NH4ClO4(s) Al2O3(s) AlCl3(s) H2O(l) N2(g) What is the minimum mass of NH4ClO4 consumed, per kilogram of Al, by the reaction of NH4ClO4 and Al? [Hint: Balance the elements in the order Cl, H, O, Al, N.] + + + +

A piece of aluminum foil measuring is dissolved in excess HCl(aq). What mass of is produced? Use equation (4.2) and for Al.

An excess of aluminum foil is allowed to react with 225mL of an aqueous solution of HCl that contains 18.0% HCl by mass. What mass of is produced? [Hint: Use equation (4.2).]

Without performing detailed calculations, which of the following metals yields the greatest amount of per gram of metal reacting with HCl(aq)? (a) Na, (b) Mg, (c) Al, (d) Zn. [Hint: Write equations similar to (4.2).]

Without performing detailed calculations, which of the following yields the same mass of per gram of compound as does ethanol, when burned in excess oxygen? (a) (b) (c) (d) CH3OCH3 ; (e) C6H5OH. HOCH2CH2OH; HOCH2C

What are the molarities of the following solutes when dissolved in water? (a) 2.92 mol in 7.16 L of solution (b) 7.69 mmol in 50.00 mL of solution (c) 25.2 g in 275 mL of solution

What are the molarities of the following solutes when dissolved in water? (a) in 125 mL of solution (b) 57.5 g in 525 mL of solution (c) 18.5 mL of in 375 mL of solution

What are the molarities of the following solutes? (a) sucrose if 150.0 g is dissolved per 250.0 mL of water solution (b) urea, if 98.3 mg of the 97.9% pure solid is dissolved in 5.00 mL of aqueous solution (c) methanol, if 125.0 mL is dissolved in enough water to make 15.0 L of solution

What are the molarities of the following solutes? (a) aspartic acid if 0.405 g is dissolved in enough water to make 100.0 mL of solution (b) acetone, if 35.0 mL is dissolved in enough water to make 425 mL of solution (c) diethyl ether, if 8.8 mg is dissolved in enough water to make 3.00 L of solution

How much (a) glucose, in grams, must be dissolved in water to produce 75.0 mL of 0.350 M ? (b) methanol, in milliliters, must be dissolved in water to produce 2.25 L of 0.485 M

How much (a) ethanol, in liters, must be dissolved in water to produce 200.0 L of 1.65 M ? (b) concentrated hydrochloric acid solution (36.0% HCl by mass; ), in milliliters, is required to produce 12.0 L of 0.234 M HCl?

In the United States, the concentration of glucose, C6H12O6, in the blood is reported in units of d = 1.18 g>mL CH3CH2OH CH3CH2OH (d = 0.789 g>mL), CH3OH? CH3OH (d = 0.792 g>mL), C6H12O6 C6H12O6 , (C2H5)2O, C3H6O, (d = 0.790 g>mL) (H2C4H5NO4) CH3OH, (d = 0.792 g>mL) CO(NH2)2 , (C12H22O11) C3H5(OH)3 (d = 1.26 g>mL) (CH3)2CO 2.25 * 10-4 mol CH3CH2OH CO(NH2)2 CH3CH2OH CH3OH milligrams per deciliter (mg/dL). In Canada, the United Kingdom, and elsewhere, the blood glucose concentration is reported in millimoles per liter (mmol/L), where 1 mmol 1 10 3 mol. If a person has a blood glucose level of 85 mg/dL, then what is (a) the blood glucose level in mmol/L; (b) the molarity of glucose in the blood?

In many communities, water is fluoridated to prevent tooth decay. In the United States, for example, more than half of the population served by public water systems has access to water that is fluoridated at approximately 1 mg F per liter. (a)What is the molarity of F in water if it contains 1.2 mg F per liter? (b) How many grams of solid KF should be added to a 1.6 108 L water reservoir to give a fluoride concentration of 1.2 mg F per liter?

Which of the following is a 0.500 M KCl solution? (a) solution; (b) 36.0 g solution; (c) 7.46 mg solution; (d) 373 g KCl in 10.00 L solution

Which two solutions have the same concentration? (a) 55.45 g solution; (b) 5.545 g g solution; (c) 55.45 g water; (d) 55.45 mg mL solution; (e) 5.00 mmol mL solution

Which has the higher concentration of sucrose: a 46% sucrose solution by mass or 1.50 M Explain your reasoning.

Which has the greater molarity of ethanol: a white wine with 11% by mass, or the solution described in Example 4-8? Explain your reasoning.

A10.00 mL sample of 2.05 M is diluted to a volume of 250.0 mL. What is the concentration of the diluted solution?

What volume of 0.750 M must be diluted with water to prepare 250.0 mL of 0.425 M

Water is evaporated from 125 mL of 0.198 M solution until the volume becomes 105 mL. What is the molarity of K2SO4 in the remaining solution?

A25.0 mL sample of HCl(aq) is diluted to a volume of 500.0 mL. If the concentration of the diluted solution is found to be 0.085 M HCl, what was the concentration of the original solution?

Given a 0.250 M stock solution, describe how you would prepare a solution that is 0.0125 M That is, what combination(s) of pipet and volumetric flask would you use? Typical sizes of vol- K2CrO4 . K2CrO4 umetric flasks found in a general chemistry laboratory are 100.0, 250.0, 500.0, and 1000.0 mL, and typical sizes of volumetric pipets are 1.00, 5.00, 10.00, 25.00, and 50.00 mL.

Given two liters of 0.496 M KCl, describe how you would use this solution to prepare 250.0 mL of 0.175 M KCl. Give sufficient details so that another student could follow your instructions.

Consider the reaction below: (a) How many grams of are required to react completely with 27.8 mL of 0.163 M (b) How many grams of are obtained from the reaction in part (a)?

Excess is added to 525 mL of 0.220 M . These substances react as follows: (a) How many grams of the will be consumed? (b) How many grams of will be produced?

How many milliliters of 0.650 M are needed to precipitate all the silver in 415 mL of 0.186 M as

Consider the reaction below. (a) How many grams of are required to react completely with 415 mL of 0.477 M HCl? (b) How many kilograms of are required to react with 324 L of a HCl solution that is 24.28% HCl by mass, and has a density of

Exactly 1.00 mL of an aqueous solution of HNO3 is diluted to 100.0 mL. It takes 29.78 mL of 0.0142 M Ca(OH)2 to convert all of the HNO3 to Ca(NO3)2. The other product of the reaction is water. Calculate the molarity of the undiluted HNO3 solution.

A5.00 mL sample of an aqueous solution of H3PO4 requires 49.1 mL of 0.217 M NaOH to convert all of the H3PO4 to Na3PO4. The other product of the reaction is water. Calculate the molarity of the H3PO4 solution.

Refer to Example 4-7 and equation (4.2). For the conditions stated in Example 4-7, determine (a) the number of moles of and (b) the molarity of the if the solution volume is simply the 23.8 mL calculated in the example. AlCl3(aq) AlCl3 Na2 Na2 Na2 1.12 g>mL? Ca(OH)2 Ca(OH)2 Ca(OH)2(s) + 2 HCl(aq) CaCl2(aq) + 2 H2O(l) Ag2CrO4(s) + 2 KNO3(aq) 2 AgNO3(aq) + K2CrO4(aq) AgNO3 Ag2CrO4(s)? K2CrO4 CuCO3(s) NaHCO3(s) CuCO3(s) + 2 NaNO3(aq) + H2O(l) + CO2(g) Cu(NO3)2(aq) + 2 NaHCO3(s) Cu(NO3)2 NaHCO3 Ag2S(s) AgNO3 ? Na2S(s) Ag2S(s) + 2 NaNO3(aq) 2 AgNO3(aq) + Na2S(aq)

Refer to the Integrative Example on page 139. If 138 g in 1.42 L of aqueous solution is treated with an excess of NO(g) and what is the molarity of the solution that results? (Assume that the reaction goes to completion.)

How many grams of will precipitate if excess is added to the 415 mL of 0.186 M in Exercise 51?

What volume of 0.0797 M is necessary to convert 9.13 g KI to in the reaction below? Assume that H2SO4 is present in excess.

How many grams of sodium must react with 155 mL to produce a solution that is 0.175 M NaOH? (Assume a final solution volume of 155 mL.)

Amethod of lowering the concentration of HCl(aq) is to allow the solution to react with a small quantity of Mg. How many milligrams of Mg must be added to 250.0 mL of 1.023 M HCl to reduce the solution concentration to exactly 1.000 M HCl?

A 0.3126 g sample of oxalic acid, requires 26.21 mL of a particular concentration of NaOH(aq) to complete the following reaction. What is the molarity of the NaOH(aq)?

A25.00 mL sample of HCl(aq) was added to a 0.1000 g sample of All the reacted, leaving some excess HCl(aq). The excess HCl(aq) required 43.82 mL of 0.01185 M to complete the following reaction. What was the molarity of the original HCl(aq)? 2 HCl(aq) + Ba(OH)2(aq) BaCl2(aq) + 2 H2O(l)

How many moles of NO(g) can be produced in the reaction of 3.00 mol and 4.00 mol 4 NH3(g) + 5 O2(g) " 4 NO(g) + 6 H2O(l) NH3(g) O2(g)?

The reaction of calcium hydride and water produces calcium hydroxide and hydrogen as products. How many moles of will be formed in the reaction between 0.82 mol CaH2(s) and 1.54 mol H2O(l)?

A0.696 mol sample of Cu is added to 136 mL of 6.0 M Assuming the following reaction is the only one that occurs, will the Cu react completely?

How many grams of are produced by the reaction of 1.84 g Al with 75.0 mL of 2.95 M HCl? [Hint: Recall equation (4.2).]

A side reaction in the manufacture of rayon from wood pulp is How many grams of are produced in the reaction of 92.5 mL of liquid and 2.78 mol NaOH?

Lithopone is a brilliant white pigment used in waterbased interior paints. It is a mixture of and ZnS produced by the reaction lithopone How many grams of lithopone are produced in the reaction of 315 mL of 0.275 M and 285 mL of 0.315 M BaS?

Ammonia can be generated by heating together the solids and and are also formed. (a) If a mixture containing 33.0 g each of NH4Cl Ca(OH)2 . CaCl2 H2O ZnSO4 BaS(aq) + ZnSO4(aq) ZnS(s) + BaSO4(s) BaSO4 CS2 (d = 1.26 g>mL) Na2CS3 3 CS2 + 6 NaOH 2 Na2CS3 + Na2CO3 + 3 H2O H2(g) 3 Cu(NO3)2(aq) + 4 H2O(l) + 2 NO(g) 3 Cu(s) + 8 HNO3(aq) HNO3. and is heated, how many grams of will form? (b) Which reactant remains in excess, and in what mass?

Chlorine can be generated by heating together calcium hypochlorite and hydrochloric acid. Calcium chloride and water are also formed. (a) If 50.0 g and 275 mL of 6.00 M HCl are allowed to react, how many grams of chlorine gas will form? (b) Which reactant, or HCl, remains in excess, and in what mass?

Chromium(II) sulfate, CrSO4, is a reagent that has been used in certain applications to help reduce carbon carbon double bonds in molecules to single bonds . The reagent can be prepared via the following reaction. 4 Zn(s) K2Cr2O7(aq) 7 H2SO4(aq) 4 ZnSO4(aq) + 2 CrSO4(aq) + K2SO4(aq) + 7 H2O(l) What is the maximum number of grams of CrSO4 that can be made from a reaction mixture containing 3.2 mol Zn, 1.7 mol K2Cr2O7, and 5.0 mol H2SO4?

Titanium tetrachloride, TiCl4, is prepared by the reaction below. 3 TiO2(s) 4 C(s) 6 Cl2(g) 3 TiCl4(g) + 2 CO2(g) + 2 CO(g) What is the maximum mass of TiCl4 that can be obtained from 35 g TiO2, 45 g Cl2, and 11 g C?

In the reaction of 277 g with an excess of HF, 187 g is obtained. What are the (a) theoretical, (b) actual, and (c) percent yields of this reaction?

In the reaction shown, 100.0 g yielded 64.0 g (a)What is the theoretical yield of the reaction? (b) What is the percent yield? (c) What mass of would produce 100.0 g if the percent yield is that determined in part (b)?

Cryolite, Na3AlF6, is an important industrial reagent. It is made by the reaction below. Al2O3(s) 6 NaOH(aq) 12 HF(g) 2 Na3AlF6(s) 9 H2O(l) In an experiment, 7.81 g Al2O3 and excess HF(g) were dissolved in 3.50 L of 0.141 M NaOH. If 28.2 g Na3AlF6 was obtained, then what is the percent yield for this experiment?

Nitrogen gas, N2, can be prepared by passing gaseous ammonia over solid copper(II) oxide, CuO, at high temperatures. The other products of the reaction are solid copper, Cu, and water vapor. In a certain experiment, a reaction mixture containing 18.1 g NH3 and 90.4 g CuO yields 6.63 g N2. Calculate the percent yield for this experiment.

The reaction of 15.0 g 22.4 g NaBr, and 32.7 g H2SO4 yields 17.1 g C4H9Br in the reaction shown. C4H9OH, + + + C6H11OH C6H10 + H2O C6H11OH C6H10 C6H10 . C6H11OH CCl4 + 2 HF CCl2F2 + 2 HCl CCl2F2 CCl4 What are the (a) theoretical yield, (b) actual yield, and (c) percent yield of this reaction?

Azobenzene, an intermediate in the manufacture of dyes, can be prepared from nitrobenzene by reaction with triethylene glycol in the presence of Zn and KOH. In one reaction, 0.10 L of nitrobenzene and 0.30 L of triethylene glycol yields 55 g azobenzene. What are the (a) theoretical yield, (b) actual yield, and (c) percent yield of this reaction? nitrobenzene triethylene glycol azobenzene

How many grams of commercial acetic acid (97% by mass) must be allowed to react with an excess of to produce 75 g of acetyl chloride if the reaction has a 78.2% yield?

Suppose that reactions (a) and (b) each have a 92% yield. Starting with 112 g in reaction (a) and an excess of how many grams of are formed in reaction (b)? (a) (b) CH3Cl + Cl2 CH2Cl2 + HCl

An essentially 100% yield is necessary for a chemical reaction used to analyze a compound, but it is almost never expected for a reaction that is used to synthesize a compound. Explain this difference.

Suppose we carry out the precipitation of described in Example 4-11. If we obtain 2.058 g of pre- Ag2CrO4(s) cipitate, we might conclude that it is nearly pure but if we obtain 2.112 g, we can be quite sure that the precipitate is not pure. Explain this difference.

How many grams of HCl are consumed in the reaction of 425 g of a mixture containing 35.2% and 64.8% by mass?

How many grams of are produced in the complete combustion of 406 g of a bottled gas that consists of 72.7% propane and 27.3% butane by mass?

Dichlorodifluoromethane, once widely used as a refrigerant, can be prepared by the reactions shown. How many moles of must be consumed in the first reaction to produce 2.25 kg in the second? Assume that all the produced in the first reaction is consumed in the second.

Carbon dioxide gas, , produced in the combustion of a sample of ethane is absorbed in producing 0.506 g How many grams of ethane must have been burned?

The following process has been used to obtain iodine from oil-field brines in California. How many kilograms of silver nitrate are required in the first step for every kilogram of iodine produced in the third step?

Sodium bromide, used to produce silver bromide for use in photography, can be prepared as shown. How iron(III) chloride + solid iodine iron(II) iodide + chlorine gas silver iodide + iron iron(II) iodide + silver silver iodide + sodium nitrate sodium iodide + silver nitrate CO2(g) + Ba(OH)2(aq) BaCO3(s) + H2O(l) CO2(g) + H2O(l) (not balanced) C2H6(g) + O2(g) (C2H6) BaCO3(s). Ba(OH)2(aq), CO2(g) CCl4 + HF CCl2F2 + HCl (not balanced) CH4 + Cl2 CCl4 + HCl (not balanced) CCl4 CCl2F2 Cl2 (C3H8) (C4H10), CO2 MgCO3 + 2 HCl MgCl2 + H2O + CO2(g) Mg(OH)2 + 2 HCl MgCl2 + 2 H2O Mg(OH)2 , MgCO3 many kilograms of iron are consumed to produce NaBr?

High-purity silicon is obtained using a three-step process. The first step involves heating solid silicon dioxide, SiO2, with solid carbon to give solid silicon and carbon monoxide gas. In the second step, solid silicon is converted into liquid silicon tetrachloride, SiCl4, by treating it with chlorine gas. In the last step, SiCl4 is treated with hydrogen gas to give ultrapure solid silicon and hydrogen chloride gas. (a) Write balanced chemical equations for the steps involved in this three-step process. (b) Calculate the masses of carbon, chlorine, and hydrogen required per kilogram of silicon.

The following set of reactions is to be used as the basis of a method for producing nitric acid, HNO3. Calculate the minimum masses of N2, H2, and O2 required per kilogram of HNO3. N2(g) 3 H2(g) 2 NH3(g) 4 NH3(g) 5 O2(g) 4 NO(g) 6 H2O(g) 2 NO(g) O2(g) 2 NO2(g) 3 NO2(g) H2O(l) 2 HNO3(aq) NO(g)

When a solid mixture of MgCO3 and CaCO3 is heated strongly, carbon dioxide gas is given off and a solid mixture of MgO and CaO is obtained. If a 24.00 g sample of a mixture of MgCO3 and CaCO3 produces 12.00 g CO2, then what is the percentage by mass of MgCO3 in the original mixture?

Amixture of Fe2O3 and FeO was analyzed and found to be 72.0% Fe by mass. What is the percentage by mass of Fe2O3 in the mixture?

Write chemical equations to represent the following reactions. (a) Limestone rock (calcium carbonate) is heated (calcined) and decomposes to calcium oxide and carbon dioxide gas. (b) Zinc sulfide ore is heated in air (roasted) and is converted to zinc oxide and sulfur dioxide gas. (Note that oxygen gas in the air is also a reactant.) (c) Propane gas reacts with gaseous water to produce a mixture of carbon monoxide and hydrogen gases. (This mixture, called synthesis gas, is used to produce a variety of organic chemicals.) (d) Sulfur dioxide gas is passed into an aqueous solution containing sodium sulfide and sodium carbonate. The reaction products are carbon dioxide and an aqueous solution of sodium thiosulfate.

Write chemical equations to represent the following reactions. (a) Calcium phosphate is heated with silicon dioxide and carbon, producing calcium silicate phosphorus and carbon monoxide. The phosphorus and chlorine react to form phosphorus trichloride, and the phosphorus trichloride and water react to form phosphorous acid. (b) Copper metal reacts with gaseous oxygen, carbon dioxide, and water to form green basic copper carbonate, (a reaction responsible for the formation of the green patina, or coating, often seen on outdoor bronze statues). (c) White phosphorus and oxygen gas react to form tetraphosphorus decoxide. The tetraphosphorus decoxide reacts with water to form an aqueous solution of phosphoric acid. (d) Calcium dihydrogen phosphate reacts with sodium hydrogen carbonate (bicarbonate), producing calcium phosphate, sodium hydrogen phosphate, carbon dioxide, and water (the principal reaction occurring when ordinary baking powder is added to cakes, bread, and biscuits).

The three astronauts aboard Apollo 13, which was launched in 1970 on April 11 and returned to Earth on April 17, were kept alive during their mission, in part, because of lithium hydroxide (LiOH) canisters that were designed to remove exhaled CO2 from the air. Solid lithium hydroxide reacts with CO2(g) to give solid Li2CO3 and water. With the assumption that an astronaut exhales approximately 1.00 kg CO2 per day, what mass of LiOH was required to remove all of the CO2 exhaled by the three-member crew on their six-day mission?

Chalkboard chalk is made from calcium carbonate and calcium sulfate, with minor impurities such as Only the reacts with dilute HCl(aq). What is the mass percent in a piece of chalk if a 3.28-g sample yields 0.981 g

Hydrogen gas, is passed over at 400 C. Water vapor is formed together with a black residue a compound consisting of 72.3% Fe and 27.7% O. Write a balanced equation for this reaction.

A sulfide of iron, containing 36.5% S by mass, is heated in and the products are sulfur dioxide and an oxide of iron containing 27.6% O, by mass. Write a balanced chemical equation for this reaction.

Water and ethanol, CH3CH2OH(l), are miscible, that is, they can be mixed in all proportions. However, when these liquids are mixed, the total volume of the resulting solution is not equal to the sum of the pure liquid volumes, and we say that the volumes are not additive. For example, when 50.0 mL of water and 50.0 mL of CH3CH2OH(l), are mixed at 20 C, the total volume of the solution is 96.5 mL, not 100.0 mL. (The volumes are not additive because the interactions and packing of water molecules are slightly different from the interactions and packing of CH3CH2OH molecules.) Calculate the molarity of CH3CH2OH in a O2(g), H2(g), Fe2O3(s) CaCl2(aq) + H2O(l) + CO2(g) CaCO3(s) + 2 HCl(aq) CO2(g)? CaCO3 SiO2 . CaCO3 Cu2(OH)2CO3 (P4), (CaSiO3), solution prepared by mixing 50.0 mL of water and 50.0 mL of CH3CH2OH(l) at 20 C. At this temperature, the densities of water and ethanol are 0.99821 g/mL and 0.7893 g/mL, respectively.

. When water and methanol, CH3OH(l), are mixed, the total volume of the resulting solution is not equal to the sum of the pure liquid volumes. (Refer to Exercise 99 for an explanation.) When 72.061 g H2O and 192.25 g CH3OH are mixed at 25 C, the resulting solution has a density of 0.86070 g/mL. At 25 C, the densities of water and methanol are 0.99705 g/mL and 0.78706 g/mL, respectively. (a) Calculate the volumes of the pure liquid samples and the solution, and show that the pure liquid volumes are not additive. [Hint: Although the volumes are not additive, the masses are.] (b) Calculate the molarity of CH3OH in this solution.

. What volume of 0.149 M HCl must be added to 1.00 102 mL of 0.285 M HCl so that the resulting solution has a molarity of 0.205 M? Assume that the volumes are additive.

. What volume of 0.0175 M CH3OH must be added to 50.0 mL of 0.0248 M CH3OH so that the resulting solution has a molarity of exactly 0.0200 M? Assume that the volumes are additive.

. What is the molarity of NaCl(aq) if a solution has 1.52 ppm Na? Assume that NaCl is the only source of Na and that the solution density is (The unit ppm is parts per million; here it can be taken to mean g Na per million grams of solution.)

. How many milligrams must be present in 50.0 L of a solution containing 2.35 ppm Ca? [Hint: See also Exercise 103.]

. A drop (0.05 mL) of 12.0 M HCl is spread over a sheet of thin aluminum foil. Assume that all the acid reacts with, and thus dissolves through, the foil. What will be the area, in of the cylindrical hole produced? (Density of foil )

. Asmall piece of zinc is dissolved in 50.00 mLof 1.035M HCl. At the conclusion of the reaction, the concentration of the 50.00 mL sample is redetermined and found to be 0.812 M HCl. What must have been the mass of the piece of zinc that dissolved?

. How many milliliters of 0.715 M solution must be diluted with water to produce 1.00 L of a solution with a concentration of 2.37 mg N/mL?

. A seawater sample has a density of 1.03 g/mL and 2.8% NaCl by mass. A saturated solution of NaCl in water is 5.45 M NaCl. How many liters of water would have to be evaporated from of the seawater before NaCl would begin to crystallize? (A saturated solution contains the maximum amount of dissolved solute possible.)

. A99.8 mL sample of a solution that is 12.0% KI bymass is added to 96.7 mL of another solution that is 14.0% by mass How many grams of should form? Pb(NO3)2(aq) + 2 KI(aq) PbI2(s) + 2 KNO3(aq) Which of the following is (are) a valid representation( s) of the contents of the reaction vessel after some disulfur dichloride (represented by red spheres) has formed?

. Solid calcium carbonate, , reacts with HCl(aq) to form and If a 45.0 g sample of is added to 1.25 L of HCl(aq) that is 25.7% HCl by mass what will be the molarity of HCl in the solution after the reaction is completed? Assume that the solution volume remains constant.

. A 2.05 g sample of an iron aluminum alloy (ferroaluminum) is dissolved in excess HCl(aq) to produce 0.105 g What is the percent composition, by mass, of the ferroaluminum?

. A 0.155 g sample of an Al Mg alloy reacts with an excess of HCl(aq) to produce 0.0163 g What is the percent Mg in the alloy? [Hint: Write equations similar to (4.2).]

. An organic liquid is either methyl alcohol ethyl alcohol or a mixture of the two. A 0.220-g sample of the liquid is burned in an excess of and yields 0.352 g Is the liquid a pure alcohol or a mixture of the two?

. The manufacture of ethyl alcohol, yields diethyl ether, as a by-product. The complete combustion of a 1.005 g sample of the product of this process yields 1.963 g What must be the mass percents of and of in this sample?

. Amixture contains only CuCl2 and FeCl3. A0.7391 g sample of the mixture is completely dissolved in water and then treated with AgNO3(aq). The following reactions occur. CuCl2(aq) 2 AgNO3(aq) 2 AgCl(s) Cu(NO3)2(aq) FeCl3(aq) 3 AgNO3(aq) 3 AgCl(s) Fe(NO3)3(aq) If it takes 86.91 mL of 0.1463 M AgNO3 solution to precipitate all the chloride as AgCl, then what is the percentage by mass of copper in the mixture?

. Under appropriate conditions, copper sulfate, potassium chromate, and water react to form a product containing and ions. Analysis of the compound yields 48.7% 35.6% and 15.7% (a) Determine the empirical formula of the compound. (b) Write a plausible equation for the reaction.

. Write a chemical equation to represent the complete combustion of malonic acid, a compound with 34.62% C, 3.88% H, and 61.50% O, by mass.

. Aluminum metal and iron(III) oxide react to give aluminum oxide and iron metal. What is the maximum mass of iron that can be obtained from a reaction mixture containing 2.5 g of aluminum and 9.5 g of iron(III) oxide. What mass of the excess reactant remains?

. Silver nitrate is a very expensive chemical. For a particular experiment, you need 100.0 mL of 0.0750 M but only 60 mL of 0.0500 M is available. You decide to pipet exactly 50.00 mL of the solution into a 100.0 mL flask, add an appropriate mass of and then dilute the resulting solution to exactly 100.0 mL. What mass of must you use?

. When sulfur and chlorine are mixed in a reaction vessel, disulfur dichloride is the sole product. The starting mixture below is represented by yellow spheres for the molecules and green spheres for the chlorine molecules. Which of the following is (are) a valid representation( s) of the contents of the reaction vessel after some disulfur dichloride (represented by red spheres) has formed?

. A method for eliminating oxides of nitrogen (e.g., NO2) from automobile exhaust gases is to pass the exhaust gases over solid cyanuric acid, C3N3(OH)3. When the hot exhaust gases come in contact with cyanuric acid, solid C3N3(OH)3 decomposes into isocyanic acid vapor, HNCO(g), which then reacts with NO2 in the exhaust gases to give N2, CO2, and H2O. How many grams of C3N3(OH)3 are needed per gram of NO2 in this method? [Hint: To balance the equation for reaction between HNCO and NO2, balance with respect to each kind of atom in this order: H, C, O, and N.]

. For a specific reaction, ammonium dichromate is the only reactant and chromium(III) oxide and water are two of the three products. What is the third product and how many grams of this product are produced per kilogram of ammonium dichromate decomposed?

. It is desired to produce as large a volume of 1.25 M urea as possible from these three sources: 345 mL of 1.29 M 485 mL of 0.653 M CO(NH2)2 , and 835 mL of 0.775 M CO(NH2)2 . How can this be done? What is the maximum volume of this solution obtainable?

. The mineral ilmenite, is an important source of titanium dioxide for use as a white pigment. In the first step in its conversion to titanium dioxide, ilmenite is treated with sulfuric acid and water to form and iron(II) sulfate heptahydrate. Titanium dioxide is obtained in two subsequent steps. How many kilograms of iron(II) sulfate heptahydrate are produced for every of ilmenite processed?

. Refer to Exercise 124. Iron(II) sulfate heptahydrate formed in the processing of ilmenite ore cannot be released into the environment. Its further treatment involves dehydration by heating to produce anhydrous iron(II) sulfate. Upon further heating, the iron(II) sulfate decomposes to iron(III) oxide, and sulfur dioxide and oxygen gases. The iron(III) oxide is used in the production of iron and steel. How many kilograms of iron(III) oxide are obtained for every of iron(II) sulfate heptahydrate?

. Melamine, is used in adhesives and resins. It is manufactured in a two-step process in which urea, is the sole starting material, isocyanic acid (HNCO) is an intermediate, and ammonia and carbon dioxide gases are by-products. (a) Write a balanced equation for the overall reaction. (b) What mass of melamine will be obtained from 100.0 kg of urea if the yield of the overall reaction is 84%?

. Acrylonitrile is used in the production of synthetic fibers, plastics, and rubber goods. It can be prepared from propylene (propene), ammonia, and oxygen in the reaction illustrated below. (a) Write a balanced chemical equation for this reaction. (b) The actual yield of the reaction is 0.73 kg acrylonitrile per kilogram of propylene. What is the minimum mass of ammonia required to produce 1.00 metric ton (1000 kg) of acrylonitrile?

. It is often difficult to determine the concentration of a species in solution, particularly if it is a biological species that takes part in complex reaction pathways. One way to do this is through a dilution experiment with labeled molecules. Instead of molecules, however, we will use fish. An angler wants to know the number of fish in a particular pond, and so puts an indelible mark on 100 fish and adds them to the pond s existing population. After waiting for the fish to spread throughout the pond, the angler starts fishing, eventually catching 18 fish. Of these, five are marked. What is the total number of fish in the pond?

. Lead nitrate and potassium iodide react in aqueous solution to form a yellow precipitate of lead iodide. In one series of experiments, the masses of the two reactants were varied, but the total mass of the two was held constant at 5.000 g. The lead iodide formed was filtered from solution, washed, dried, and weighed. The table gives data for a series of reactions. (a) Plot the data in a graph of mass of lead iodide versus mass of lead nitrate, and draw the appropriate curve(s) connecting the data points. What is the maximum mass of precipitate that can be obtained? (b) Explain why the maximum mass of precipitate is obtained when the reactants are in their stoichiometric proportions. What are these stoichiometric proportions expressed as a mass ratio, and as a mole ratio? (c) Show how the stoichiometric proportions determined in part (b) are related to the balanced equation for the reaction.

. The emerging field of green chemistry comprises all the methods used to minimize the environmental impact of chemical activities. One of the dozen or so factors in green chemistry is atom economy the efficiency in rearranging the atoms in a set of reactants into the desired product. Atom economy (AE) is expressed as a percentage by the equation For example, when burns in the sole product is All the atoms of the reactants appear in the product and the atom economy is 100%, as implied by the equation For the Raschig process described in the Focus On feature for Chapter 4 on www.masteringchemistry.com, (a) what is the theoretical maximum AE for the synthesis of hydrazine (equation 4B)? (b) Why is the actual AE less than that calculated in part (a)? (c) Explain why substituting acetone for water improves the AE. (d) Propose a reaction for the synthesis of hydrazine that would have a theoretical AE of 100%.

. Baking soda, is made from soda ash, a common name for sodium carbonate. The soda ash is obtained in two ways. It can be manufactured in a process in which carbon dioxide, ammonia, sodium chloride, and water are the starting materials. Alternatively, it is mined as a mineral called trona (left photo). Whether the soda ash is mined or manufactured, it is dissolved in water and carbon dioxide is bubbled through the solution. Sodium bicarbonate precipitates from the solution. As a chemical analyst you are presented with two samples of sodium bicarbonate one from the manufacturing process and the other derived from trona. You are asked to determine which is purer and are told that the impurity is sodium carbonate. You decide to treat the samples with just sufficient hydrochloric acid to convert all the sodium carbonate and bicarbonate to sodium chloride, carbon dioxide, and water. You then precipitate silver chloride in the reaction of sodium chloride with silver nitrate. A 6.93 g sample of baking soda derived from trona gave 11.89 g of silver chloride. A 6.78 g sample from manufactured sodium carbonate gave 11.77 g of silver chloride. Which sample is purer, that is, which has the greater mass percent NaHCO3 ?

. In your own words, define or explain these terms or symbols. (a) (b) (aq) (c) stoichiometric coefficient (d) overall equation

. Briefly describe (a) balancing a chemical equation; (b) preparing a solution by dilution; (c) determining the limiting reactant in a reaction.

. Explain the important distinctions between (a) chemical formula and chemical equation; (b) stoichiometric coefficient and stoichiometric factor; (c) solute and solvent; (d) actual yield and percent yield; (e) consecutive and simultaneous reactions.

. When the equation below is balanced, the correct set of stoichiometric coefficients is (a) (b) (c) (d)

. A reaction mixture contains 1.0 mol (calcium cyanamide) and 1.0 mol . The maximum number of moles of produced is (a) 3.0; (b) 2.0; (c) between 1.0 and 2.0; (d) less than 1.0.

. Consider the chemical equation below. What is the maximum number of moles of K2SO4 that can be obtained from a reaction mixture containing 5.0 moles each of KMnO4, KI, and H2SO4? (a) 3.0 mol; (b) 3.8 mol; (c) 5.0 mol; (d) 6.0 mol; (e) 15 mol. 2 KMnO4 10 KI 8 H2SO4 6 K2SO4 2 MnSO4 + 5 I2 + 8 H2O

. In the decomposition of silver(I) carbonate to form metallic silver, carbon dioxide gas, and oxygen gas, (a) one mol of oxygen gas is formed for every 2 mol of carbon dioxide gas; (b) 2 mol of silver metal is formed for every 1 mol of oxygen gas; (c) equal numbers of + + + CaCN2(s) + 3 H2O(l) CaCO3 + 2 NH3(g) NH3 H2O CaCN2 ? Cu(NO3)2(aq) + ? H2O(l) + ? NO(g) ? Cu(s) + ? HNO3(aq) 3, 8 3, 4, 2. 1,4 1, 2, 2; 2, 6 2, 3, 2; 1, 6 1, 3, 4; " moles of carbon dioxide and oxygen gases are produced; (d) the same number of moles of silver metal are formed as of the silver(I) carbonate decomposed.

. To obtain a solution that is 1.00 M you should prepare (a) 1.00 L of aqueous solution containing 100 g (b) 1 kg of aqueous solution containing 85.0 g (c) 5.00 L of aqueous solution containing 425 g (d) an aqueous solution containing 8.5 mg

. To prepare a solution that is 0.50 M KCl starting with 100.0 mL of 0.40 M KCl, you should (a) add 20.0 mL of water; (b) add 0.075 g KCl; (c) add 0.10 mol KCl; (d) evaporate 20.0 mL of water.

. An aqueous solution that is 5.30% LiBr by mass has a density of 1.040 g/mL. What is the molarity of this solution? (a) 0.563 M; (b) 0.635 M; (c) 0.0635 M; (d) 0.0563 M; (e) 12.0 M.

. In the reaction of 2.00 mol with an excess of HF, 1.70 mol is obtained. (a) The theoretical yield is 1.70 mol (b) The theoretical yield is 1.00 mol (c) The theoretical yield depends on how large an excess of HF is used. (d) The percent yield is 85%.

. The incomplete combustion of gasoline produces CO(g) as well as Write an equation for (a) the complete combustion of the gasoline component octane, and (b) incomplete combustion of octane with 25% of the carbon appearing as CO(g).

. The minerals calcite, magnesite, and dolomite, , decompose when strongly heated to form the corresponding metal oxide(s) and carbon dioxide gas. A 1.000-g sample known to be one of the three minerals was strongly heated and 0.477 g was obtained. Which of the three minerals was it?

. A 1.000 g sample of a mixture of CH4 and C2H6 is analyzed by burning it completely in O2, yielding 2.776 g CO2. What is the percentage by mass of CH4 in the mixture? (a) 93%; (b) 82%; (c) 67% ; (d) 36%; (e) less than 36%.

. Nitric acid, HNO3, can be manufactured from ammonia, NH3, by using the three reactions shown below. Step 1: 4 NH3(g) 5 O2(g) 4 NO(g) 6 H2O(l) Step 2: 2 NO(g) O2(g) 2 NO2(g) Step 3: 3 NO2(g) H2O(l) 2 HNO3 + : (aq) + NO(g) + : + : + What is the maximum number of moles of HNO3 that can be obtained from 4.00 moles of NH3? (Assume that the NO produced in step 3 is not recycled back into step 2.) (a) 1.33 mol; (b) 2.00 mol; (c) 2.67 mol; (d) 4.00 mol; (e) 6.00 mol.

. Appendix E describes a useful study aid known as concept mapping. Using the method presented in Appendix E, construct a concept map relating the topics found in Sections 4-3, 4-4, and 4-5.